Ball and socket joint, preferably for chassis components of motor vehicles, with a tubular joint housing (8) forming a cylindrical interior in which a metal inner part (1) and an elastomer body (5) enclosing the inner part (1) and adhered to said inner part (1) are accommodated, said elastomer body (5) is axially compressed in the axial longitudinal direction of the ball and socket joint with thrust rings (6, 7) inserted in between and adheringly joined to the elastomer body constituting bearing shells which co-operate with matching projections (10) projecting into the interior of the joint housing (8), and at least one of the projections is provided by means of a resilient retaining ring (11) inserted in a radial recess (12) of the interior of the joint housing (8), the side face of which directed towards the centre of the interior sits in contact with one of the axial thrust ring external faces (13), characterized in that the thrust ring (6) co-operating with the resilient retaining ring (11) has a recess (14) in its axial external face (13) directed towards the resilient retaining ring (11) extending radially around the outer edge of the thrust ring (6) in which the resilient retaining ring (11) locates when the ball and socket joint is in the assembled state and in that the depth of the recess (14) in the axial longitudinal direction of the ball and socket joint is approximately half the thickness of the resilient retaining ring (11). Dated this 27th day of January, 2005.

The following specification particularly describes the invention and the manner in which it is to be performed : -
31-10-2006
3 1 OCT 2006

Description
The invention relates to a ball and socket joint, preferably for chassis components of motor vehicles, having the generic features outlined in the introductory part of claim 1.
The described ball and socket joints are preferably used
in chassis modules for utility vehicles. In principle,
joints of this type have proved to be effective in the
prior art. Under normal operating conditions, radial,
axial and joint movements of the inner part relative to
the housing are obtained by elastic deformations of the
elastomer body which is axially compressed. Axial
compression is imparted during assembly of the ball and
socket joint, when the inner part with the elastomer body
adhered to it and bearing shells in the form of thrust
rings disposed in the axial direction and adhered
thereto, enclosing the elastomer body, are placed in the
housing, after which the elastomer body is compressed to
a defined degree via the thrust rings, preferably by
means of a press, and the resilient retaining ring is
simultaneously inserted in the radial recess of the
interior of the joint housing, as a result of which the
oppositely lying thrust rings sit on a shoulder machined
in the housing so that the elastomer body is not able to
relax again or is so to only a slight degree.
In practice, it has been found that under specific,

extreme operating conditions when the ball and socket joint is under dynamic load, such as can occur during driving operation, relative displacements can occur between the elastomer body and the thrust rings adhered to them as well as the resilient retaining ring. In individual cases, this runs the risk of the resilient retaining ring springing out of the radial recess of the joint housing in which it is inserted, impairing the function of the ball and socket joint due to impact.
Accordingly, the objective of the present invention is to improve a ball and socket joint of the generic type outlined above so that the ball and socket joint is guaranteed to function reliably, even under extreme operating conditions, by ensuring that the retaining ring used, which offers an inexpensive and simple means of pre-tensioning the elastomer body of the ball and socket joint, remains at all times in the position in which it is secured during assembly.
This objective is achieved by means of the generic features outlined in the introductory part of claim 1 in conjunction with the technical teaching disclosed in the characterising part. For the purpose of the invention, the thrust ring of the elastomer body co-operating with the resilient retaining ring has a recess in its axial external face directed towards the resilient retaining ring, extending radially along the outer edge of the thrust ring, in which the resilient retaining ring locates when the ball and socket joint is in the assembled state.
The possibility of the resilient retaining ring springing

out of the recess provided in the joint housing due to radial deformation of the resilient retaining ring can be reliably ruled out as a result of this combination of features proposed by the invention.
This being the case, in one advantageous embodiment, it is sufficient if the depth of the recess in the axial direction of the ball and socket joint is approximately half the thickness of the resilient retaining ring used.
An example of an embodiment of the subject matter of the invention will be explained in more detail with reference to the appended drawings.
Of these:
Figure 1 is a diagram showing a bisection through a ball and socket joint proposed by the invention
and
Figure 2 is a diagram showing detail A from Figure 1 on a larger scale.
As illustrated in the diagram of Figure 1, the ball and socket joint consists of an inner part 1, which has mounting pins 2 and 3 at the two free ends to provide a connection to a motor vehicle part. The central, spherically shaped middle region 4 of the inner part 1 is enclosed by an elastomer body 5, which is adheringly joined to the inner part 1, for example by a vulcanisation process. Disposed on the end faces of the elastomer body 5 as viewed in the axial direction of the ball and socket joint are respective thrust rings 6 and 7, which are adheringly joined to the elastomer body. The

elastomer body 5, together with the thrust rings 6 and 7, is accommodated in a joint housing 8 which is essentially of a tubular design and forms a cylindrical interior 9. The cylindrical interior 9 is provided with a peripheral shoulder 10 at one end, on which the thrust ring 7 is supported. When the ball and socket joint is in the assembled state, the other thrust ring 6 is supported on a resilient retaining ring 11, which is inserted in a peripheral, radial recess 12 of the interior of the joint housing. The recess is provided in the form of a U-shaped groove. In the non-assembled state, the width of the elastomer body 5 in the axial longitudinal direction is bigger than the width between the internal face of the shoulder 10 and the internal face of the resilient retaining ring 11 inside the joint housing 8. During the assembly process, the elastomer body is therefore compressed in the axial direction to the degree that the resilient retaining ring 11 can be inserted in the recess 12 provided for this purpose in the cylindrical interior 9 of the joint housing 8. Consequently, the elastomer body 5 is not able to relax again and is therefore pre-tensioned accordingly.
In order to ensure that the resilient retaining ring 11 always remains in the position in the recess 12 illustrated in Figure 1 under all operating conditions, including in particular when the ball and socket joint is subjected to high dynamic load, the ball and socket joint proposed by the' invention has the specific feature illustrated by detail A from Figure 1 shown on an enlarged scale in Figure 2.
In Figure 2, the region where the elastomer body 5 is

secured to the adjacent thrust ring 6 is constituted by the resilient retaining ring 11 which is accommodated in the recess 12 of the joint housing 8. Accordingly, the technical teaching of the invention is based on the fact that the thrust ring 6 co-operating with the resilient retaining ring 11 has a recess 14 on its axial external face 13 directed towards the resilient retaining ring. This recess is disposed extending round the outer edge of the thrust ring 6 and has an essentially rectangular cross-section. The diameter of the radial boundary surface 15 is therefore such that it is only slightly smaller than the smallest internal diameter of the resilient retaining ring 11.
As may also be seen from the diagram given in Figure 2, the dimension T denoting the depth of the recess 14 is essentially half the size of the thickness S of the resilient retaining ring 11. The geometric design and the dimension of the recess 14 ensure that, once the resilient retaining ring 11 has been fitted, it is not able to snap out of the recess 12 as a result of dynamic loads.